ISO 6743-5:2006

Overview - ISO 6743-5:2006 (Family T, Turbines)

ISO 6743-5:2006 defines a detailed classification system for turbine lubricants within ISO’s class L (lubricants, industrial oils and related products). Known as Family T, the standard assigns concise alphanumeric codes (for example ISO‑L‑TSA 46 or L‑TSA 46) to lubricants intended for steam, gas, combined‑cycle, gearbox and hydraulic turbine applications. The standard is intended to be read with ISO 6743‑99 and connects lubricant type codes to application‑specific characteristics and viscosity classes (per ISO 3448).

Key topics and technical requirements

• Classification principle: a code beginning with T identifies turbine family products; additional letters denote product categories and may be suffixed with a viscosity class number in accordance with ISO 3448.
• Categories cover major turbine applications and performance needs, for example:
  • Steam turbines (TSA, TSE, TSD, TCD) - mineral and phosphate‑ester types; fire‑resistant options
  • Gas turbines (TGA, TGB) - mineral oils for normal and high temperature service
  • Synthetic gas turbine fluids (TGCH, TGCE) - polyalphaolefins, esters and other synthetics for enhanced oxidation, low‑temperature or environmental properties
  • Combined‑cycle / single‑shaft turbines (TGSB, TGSE) - oils suitable where one lubricant serves both gas and steam sections
  • Hydraulic turbines (THA, THCH, THCE, THE) - mineral and synthetic fluids including low‑toxicity/environment‑acceptable types and high‑load formulations
• Updates in the 2006 edition: inclusion of synthetic oils, fluids for combined‑cycle and single‑shaft turbines, aviation‑derived synthetics for on‑shore use, and environmental‑acceptable fluids for hydraulic turbines.
• Not covered: aviation turbine oils (except where used on‑shore and compatible with listed T‑types) and wind‑turbine gearbox oils (covered by other parts).

Practical applications - who uses this standard

• Turbine OEMs and power plant engineers for specifying appropriate oils for steam, gas, combined‑cycle and hydraulic turbines
• Maintenance and reliability teams for lubricant selection, inventory control and change‑out decisions
• Lubricant manufacturers and suppliers for product classification, labeling and marketing
• Procurement and specifications writers for consistent contract language and regulatory compliance (e.g., environmental acceptance)
• Technical consultants and standards committees aligning plant practices with international classification

Benefits

• Simplifies lubricant selection and cross‑referencing
• Supports safety (fire‑resistant and low‑toxicity options), performance (oxidation, load capacity) and environmental compliance
• Facilitates consistent procurement and maintenance documentation

Related standards

• ISO 6743‑99 (Generalities)
• ISO 3448 (Viscosity classification)
• ISO 6743‑6 / ISO 12925‑1 (gear oils and gearbox specifications)